North Korea is threatening to cancel the much-anticipated summit with the United States, and it has already cancelled high-level meetings with South Korea, because South Korea and the U.S. are conducting a military drill, South Korean news agency Yonhap reported Tuesday.

“The North’s Korean Central News Agency said the Max Thunder drills between the South Korean and U.S. air forces are a rehearsal for invasion of the North and a provocation amid warming inter-Korean ties,” South Korean news agency Yonhap reported.

“This exercise targeting us, which is being carried out across South Korea, is a flagrant challenge to the Panmunjom Declaration and an intentional military provocation running counter to the positive political development on the Korean Peninsula. The United States will also have to undertake careful deliberations about the fate of the planned North Korea-U.S. summit in light of this provocative military ruckus jointly conducted with the South Korean authorities.”

North Korea views such military drills as practice for invasion of its country.

North Korean state media KCNA recently reported on a press release from the North Korean regime that officials have scheduled a ceremony to dismantle the country’s nuclear site on May 23, and they are inviting international press to attend in a rare opening up of the regime unlike the world has ever seen before.

This development comes days after North Korea released three American detainees to Secretary of State Pompeo on his second visit to the isolated regime in weeks, and President Trump announcing that the highly anticipated summit with Kim Jong Un will be held in Singapore on June 12.